Constellations come out tonight

April 29, 2014

After having brightened the sky through our long winter nights, the lovely constellations of Taurus with the Pleaides, Orion with his jeweled belt, Canis Major with dazzling bright Sirius, Canis Minor, Gemini still hosting Jupiter, and Auriga drop abruptly out of the sky as the evenings lengthen.

As the skies darken after sunset tomorrow night, these constellations will emerge from the dusk above the western horizon. If you have a low horizon, sharp eyes and good binoculars, you may be able to spot a thin crescent moon just below the line along Orion's belt to the Pleiades.

It will be just below the V of Taurus' nose with Aldebaran (al-DEB-uh-ron, "The Follower" of the Pleiades) marking the top left end.

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This is the best time of year to spot a young moon since its orbital path is inclined steeply to the horizon. The thinner the crescent, the brighter the Earth shine on the rest of the moon appears. Keep in mind that at new moon, the moon sees a full Earth which is much bigger and brighter than any full moon! The Earth shine is the light that has reflected off Earth to illuminate the dark side of the moon ... bouncing from the sun to Earth, to the moon and back to Earth!

On May Day, a thicker crescent moon will be easier to spot right above Aldebaran. It will rise higher each night to be just below Jupiter on May 3 and left (south) of it on May 4. Procyon (PRO-see-on) will be at a nearly equal distance to the moon's left that night.

Take a few minutes to pause on a clear evening this week to bid these lovely constellations adieu until they rise again next winter.

Meanwhile in the east, Mars shines almost as bright as Sirius. As shown in the diagram, it is in the constellation of Virgo. As Earth has been passing it on the great racetrack of the Solar System, it has been moving westward with respect to the stars. This began on March 1, 2014. On April 8, it was at opposition as Earth passed directly between it and the sun. Due to the ovalness of its orbit, though, it was closest to Earth on April 14, a mere 57 million miles distant. That was also when it was a bit brighter than Sirius. It's slowly fading as Earth moves away from it, but its ruddy color is unmistakable.

In its retrograde loop, Mars will move slightly past Porrima (poor-EE-ma), then stop on May 20 to resume its prograde, eastward motion. As the circles on the diagram show, we will be able to watch through the warm nights of summer as it picks up speed to catch up with Saturn in Libra at the end of August. On Aug. 19, Mars, Zubenelgenubi (ZOO-ben-ell-gen-OO-bee) and Saturn will be aligned in the western sky just after sunset. On the previous morning, Aug. 18, Venus and Jupiter will be about a quarter of a degree apart right next to the Beehive star cluster in Cancer just before dawn. It will be a delightful sight viewed in binoculars or a telescope.

Back to April, Saturn will rise tonight just before 9 pm. It, too, is in retrograde motion as Earth catches up to pass it. On May 9, it will rise just after 8 p.m. and be directly on the line between Zubeneschamali (ZOO-ben-esh-uh-MALL-ee) and Brachium (BRAY-key-um). On May 10 Saturn will be at opposition and 827 million miles from Earth. Evan at that distance, sunlight reflecting off its clouds make it appear brighter than Spica (SPIKE-uh), above and right (south) of it, but not quite as bright as Vega (VEE-guh) at about the same altitude (angle above the horizon) 90 degrees to its north (left). As the diagram shows, it will continue moving westward until July 20, after which it will resume its eastward motion. Mars will catch up and be closest to Saturn on Aug. 26.

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With our roll-off roof facility up and running, astronomers of the Adirondack Public Observatory are eager to dazzle you with telescopic views of the cosmos on the first and third Fridays of the month (next on May 2), starting 30 minutes after sunset. Go to apobservatory.org and click on "events" for more information and directions to our site above Little Wolf Pond in Tupper Lake. Listen for me on North Country Public Radio about once a month during "The Eight O'Clock Hour" or email me with any questions at aodonoghue@stlawu.edu.